Back mounted underwater propulsion assembly for divers



June 9, 1964 A. BOATWRIGHT 3,136,279

BACK MOUNTED UNDERWATER PROPULSION ASSEMBLY FOR DIVERS Filed Dec. 14, 1961 Boafwrighf I N VEN TOR.

Mafia... BY MW HMDECJ Albert J 1964 A. BOATWRIGHT BACK MOUNTED UNDERWATER PROPULSION ASSEMBLY FOR DIVERS Filed Dec. 14, 1961 an...) M.

INVENTOR. Wau h. BY ra a/y fiM a- United States Patent 3,136,279 BACK MOUNTED UNDERWATER PROPULSION ASSEMBLY FOR DIVERS Albert Boatwright, 10020 Nicaragua Drive, Miami, Fla. Filed Dec. 14, 1961, Ser. No. 159,365 Claims.- (Cl. 115-6.1)

This invention relates to a novel and useful back.

mounted underwater propulsion assembly for divers and more specifically to a back mounted compressed air tank support which is also provided with a fluid motor including a rotatable output shaft which has a screw-type propeller mounted thereon. The back mounted underwater propulsion assembly includes means for also supporting a tank of compressed carbonic gas and the tank of compressed carbonic gas is utilized as a power supply for the fluid motor.

Skindivers and the like who normally carry their own supply of compressed air for breathing under water quite often are desirous of being able to remain below the surface of a body of water for extended periods of time and if a dive of any great duration is to be performed, a skindiver must be supplied with at least two tanks of compressed air. However, a skindiver may use tanks of compressed oxygen rather than air and accomplish dives of longer duration. 1

Inasmuch as it is considerably more expensive for a diver to use compressed oxygen, most skindivers use compressed air. However, when making dives of long duration, the skindiver must of course exert himself to be propelled through the water and consequently a skindiver uses up his supply of compressed air at a very fast pace and at a pace considerably faster than that which he would use air if he had a means to propel himself through the water and could remain substantially relaxed at all times. I

While it is possible to compress air into a liquid state and thus have a greater supply of air on hand in a given tank, if air is compressed to the liquid state, there is atendency for the oxygen in the air to vaporize more readily than the carbox dioxide which results in a skindiver receiving a greater proportion of oxygen during the beginning of his dive and a greater proportion of carbon dioxide toward the end of his dive. This of course can be extremely dangerous.

In order that a skindiver may achieve dives of greater duration while being supplied with only compressed air, it is the main object of this invention to provide a back mounted underwater propulsion assembly for divers which has a fluid motor mounted thereon and means for supporting a tank of compressed carbonic gas. As carbonic gas may more readily be compressed to a liquid state, a large supply of carbonic gas may be provided in a conventional skindiving pressure tank. The fluid motor is provided with a rotatable output shaft and a screw-type propeller is mounted thereon, whereby the skindiver may use his large supply of liquefied carbon gas as a propulsion force to propel him through the water thereby enabling the skindiver to be relatively relaxed and thus require far less air or oxygen.

A furtherobject of this invention, in accordance with the preceding object, is to provide a back mounted underwater propulsion assembly which may be readily removably secured to the back of a skindiver.

- Still another object of this invention in accordance with the immediately preceding object is to provide a back mounted underwater propulsion assembly which a skindiver may with very little effort manipulate in applying the underwater propulsion assembly to his back.

Another object of this invention is to provide a control 3,136,279 Patented June .9, 1964.

sage to the fluid motor.

1 Another object of this invention in accordance with the 7 immediately preceding object is to provide a fluid conduit operatively connected to the fluid motor at one end and adapted for connection to a tank of liquefied carbonic gas at the other end and with heat exchange means and expansion valve means disposed in a fluid conduit with the heat exchange means disposed downstream of the expansion valve in order that the temperature of the ambient Water may be utilized to raise the temperature of the carbonic gas after it has been expanded.

Still another object of this invention is to provide a back mounted underwater propulsion assembly for divers which may be readily adjusted and adapted for securement to the back of various sizes of skindivers.

A final object to be specifically enumerated herein is to provide a back mounted underwater propulsion assembly which will conform to conventional forms of manufacture, be of simple construction and easy to use 1 so as to provide a device that will be economically feasible, long lasting and relatively trouble free in operation.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

FIGURE 1 is a perspective view of a skindiver with the back mounted underwater propulsion assembly of the instant invention mounted on the back of the skindiver;

FIGURE 2 is an enlarged perspective view of the back mounted underwater propulsion assembly as seen from the front, the outline of a diver being shown in phantom lines;

FIGURE 3 is a perspective view of the frame of the back mounted underwater propulsion assembly;

FIGURE 4 is an enlarged fragmentary sectional view taken substantially upon the plane indicated by section line 4-.4 of FIGURE 2;

FIGURE 5 is an enlarged perspective view of the underwater propulsion assembly as seen from the rear, parts thereof being broken away and shown in section;

FIGURE 6 is a fragmentary longitudinal vertical sectional view taken substantially upon the plane'passing through the longitudinal center line of the propulsion assembly;

FIGURE 7 is an enlarged fragmentary sectional view taken substantially upon the plane indicated by section line 77 of FIGURE 6;

FIGURE 8 is an enlarged fragmentary longitudinal vertical sectional view taken substantially upon the plane passing through the longitudinal center line of the fluid motor of the underwater propulsion assembly; and

FIGURE 9 is a transverse sectional view taken substantially upon the plane indicated by section line 99 of FIGURE 8. I v

Referring now more specifically to the drawings, the numeral 10 generally designates the back mounted under- 1 water propulsion assembly of the instant invention which includes a back mounted plate generally referred to by the reference numeral 12. As can best be seen from FIGURES 3, 5 and 6 of the drawings, the back mounting plate 12 includes an upper marginal edge portion 14 and a lower marginal edge portion 16. A pair of laterally spaced inverted U-shaped and forwardly projecting and downwardly opening shoulder hanger portions generally assembly whereby the supply of carbonic gas from a tank generally referred to by the reference numeral 22. The

. 3 7 frame portion 22 includes a main back body portion 24 and a pair of generally inverted U-shaped bracing members 26 and 28. The frame portion 22 and the bracing members 26 and 28 are covered-with a waterproof and resilient covering such as rubber or plastic and the covering is generally designated by the reference numeral 30, see FIGURES 2 and 3.

From FIGURE 2 of the drawings it will be noted that the main body portion of the back mounting plate 12 conforms to and overlies the back of the diver generally referred to by the reference numeral 32 and that the inverted U-shaped, forwardly projecting and downwardly opening shoulder hanger portions embrace the shoulders 34 and 36 of the diver 32.

An adjustable clamp assembly generally referred to by. the reference numeral 38 is carried by the lower marginal edge portion 16 of the back mounting plate 12 and includes a pivoted actuator 40 for effecting a clamping action by means of the clamp assembly 38.

A generally J-shaped, forwardly projecting and upwardly opening crotch engaging member generally referred to by the reference numeral 42 is provided and the long leg 44 thereof is hollow and has one end of a coil spring 46 secured therein. The end of the coil spring which projects outwardly of the long leg 44 is eccentrically disposed relative to the longitudinal center line of the long leg 44 and is clampingly received in the clamp assembly 38. The short leg 48 and the bight portion 50 of the J-shaped crotch engaging member 42 together with the long leg 44 may be covered with a suitable waterproof and resilient cover similar to the covering 30. From FIGURES 1 and 2 of the drawings it will be noted that the J-shaped crotch engaging member is received between the legs 52 and 54 of the diver' and prevents the back mounted plate 12 from riding upwardly on the back of the diver 32.

Additionally, it will be noted that the large diameter end portion 56 of the spring 46 which is disposed in the upper end of the long leg 44 is threadedly engaged therein whereby the long leg 44 may be eccentrically adjusted relative to the longitudinal center line of the opening extending through the clamp assembly 38.

A large diameter fluid conduit generally referred to by the reference numeral 58 is secured to the frame portion 22 in any convenient manner such as by welding 60 and is also generally J-shaped in configuration. The long leg 62 generally parallels the back mounting plate 12 and the back portion is carried by the lower end of the long leg 62 and curves rearwardly and is defined by the reference numeral 64. The free end of the bight portion 64 has a fitting generally referred to by the reference numeral 66 secured thereto by means of mating flanges 68 and 70 formed on the fitting 66 and the free end of the bight portion 64 respectively. The flanges 68 'and 70 are secured together in any convenient manner such as by fasteners 72 and an annular sealing washer 74 is secured between the confronting surfaces of the flanges 68 and 70. The end of the fitting 66 remote from the flange 70 has a sealed union 75 secured thereto which has an opening or pressure inlet passage 76formed therethrough. The union 75 comprises the inlet for the fluid motor which is generally referred toby the reference numeral 78. The fluid motor 78 is secured within a housing generally referred to by the reference numeral 80 by means of an O-ring or snap ring 82 and is provided with an output shaft 84 on which there is mounted a screw-type of propeller 86. A shroud assembly generally referred to by the reference numeral 88 is mounted from the housing 80 and encloses the screw-type propeller 86. The case.

90 of the fluid motor 78 is provided with a plurality of exhaust slots 92 and these slots are in communication with the rear end of the housing 80 which has a flexible and resilient exhaust valve generally referred to by the reference numeral 94 secured thereto. It is to be noted that the exhaust valve 94 is flat and that its outlet end 4 has a slit formed therein which would normally be closed by means of the pressure of the ambient water when the skindiver 32 is beneath the surface and is not utilizing the fluid motor 78.

With attention now directed to FIGURES 2, 5 and 7 of the drawings it will be noted that the upper end of the long leg 62 has a pressure reduction valve assembly generally referred to by the reference numeral 96 secured therein which includes a small diameter orifice 98. The outlet end of a fluid pressure line 100 is secured to the pressure reduction valve 96 and extends through an apertured resilient tubing 102 carried by the shoulder hanger portion 20 to a point on the free end of the shoulder hanger portion 20 and then doubles back over the shoulder hanger portion 20 and is provided with a fitting 104 on its inlet end adapted for securement to the outlet valve 106 of a tank 108 which contains compressed carbonic gas.

A simple on-oif control and pressure reduction valve assembly generally referred to by the reference numeral 110 is disposed in the fluid pressure line .100 on the forwardmost end of the shoulder hanger portion 20 and it will be noted that the back mounting plate 12 is provided with a plurality of pairs of apertures 112 by which the tank 168 of compressed carbonic gas and the tank 114 of compressed air or oxygen may be secured to the back mounting plate 12.

It is to be understood that the tank 114 is provided with a suitable control valve assembly 116 and that air lines 118 and 120 extend to the mouth piece 122 once it is disposed in the mouth of the diver 32.

The portion of the fluid pressure line 100 disposed in the covering or tubing 102 is coiled and thus constitutes a heat exchanger whereby the extremely cool vaporized carbonic gas after passing through the on-oif control and pressure reduction valve 110 may be warmed by the temperature of the ambient water. In this matter, far more effective and economical use of pressurized carbonic gas may be obtained and thus the fluid motor 78 may be operated for extended periods of time from only one tank of compressed carbonic gas.

The fluid conduit 58 is constructed of aluminum and is approximately one-quarter inch in diameter. The onoff control and expansion valve 110 will reduce the pressure in the fluid pressure line from an extremely high pressure between the control valve and.the tank 108 to a pressure of approximately 600 to 700 p.s.i. At this pressure, the gas is then passed through the coiled portion of the. fluid pressure line 100 where it absorbs heat from the ambient water. Then, as the carbonic gas passes through the orifice 98, the gas is further expanded and reduced in pressure to about 110 p.s.i. and the aluminum construction of the fluid conduit 58 will further serve to raise the temperature of the quite expanded carbonic gasand also act as a surge chamber to eliminate intermittent surges of pressure to the motor 78 caused by tiny flecks of ice brought about by pressure reductions of the carbonic gas at the "control valve 110 and at the orifice 98.

The pressure reduction and on-off control valve assembly 110 includes an actuator 124 which may be readily controlled by the diver 32 and a flexible pull cable 126 is slidingly received in a guiding tube 128 secured to the back mounting plate 12 and has a handle 130 secured to its forward end for manipulation by the diver. The other end of the cable 126 is secured to the actuator 40. In this manner, the positioning of the J-shaped crotch engaging member 42 may be readily adjusted by the diver 32 by manipulating the J-shaped crotch engaging member 42 with one handand the clamp assembly 38, actuator cable 126 with the other hand.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention J1 to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention as claimed.

What is claimed as new is as follows:

1. A back mounted underwater propulsion assembly for divers comprising a back mounting plate having upper and lower marginal edge portions and adapted to conform to and overlie the back of a diver, said upper marginal edge portion including a pair of laterally spaced inverted U-shaped forwardly projecting and downwardly opening shoulder hanger portions, means on said back mounting plate adapted to have at. least one compressed fluid tank secured thereto, a generally U-shaped forwardly projecting and upwardly opening crotch engaging member carried by the lower edge portion of said back mounting plate, means mounting said crotch engaging member on said back mounting plate for adjustable positioning toward and away from said upper marginal edge portion, said mounting means including means eccentrically mounting said crotch engaging member for adjustable positioning about an axis generally paralleling said mounting plate and extending from the upper marginal edge portion to the lower marginal edge portion of said mounting plate.

2. The combination of claim 1 wherein said back mounting plate comprises a semi-rigid frame covered with a water proof and flexible and resilient material.

3. The combination of claim 1 wherein said back mounting plate has a fluid motor having a fluid inlet and outlet mounted thereon spaced rearwardly of said mounting plate and provided with a rotatable output shaft having a screw propeller mounted thereon.

4. The combination of claim 3 including a compressed fluid conduit having an inlet end disposed rearwardly of said mounting plate and which extends over one of said shoulder hanger portions to the front of said mounting plate and then back over said shoulder hanger portion to the rear of said mounting plate and is provided with an outlet end communicated with the fluid inlet of said motor.

5. A back mounted underwater propulsion assembly for divers comprising a back mounting plate having upper and lower marginal edge portions and adapted to conform to and overlie the back of a diver, said upper marginal edge portion including a pair of laterally spaced inverted U-shaped forwardly projecting and downwardly opening shoulder hanger portions, means on said back mounting plate adapted to have at least one compressed fluid tank secured thereto, a generally J-shaped forwardly projecting and upwardly opening crotch engaging member carried by the lower edge portion of said back mounting plate, means mounting said crotch engaging member on said back mounting plate for adjustable positioning toward and away from said upper marginal edge portion, said back mounting plate having a fluid motor including a fluid inlet and a fluid outlet, said fluid motor being mounted from said mounting plate and spaced rearwardly thereof and provided with a rotatable output shaft having a screw propeller mounted thereon, a compressed fluid conduit having an inlet end disposed rearwardly of said mounting plate and which extends over one of said shoulder hanger portions to the front of said mounting plate and then back over said shoulder hanger portion to the rear of said mounting plate and is provided with an outlet end communicated with the fluid inlet of said motor, the portion of said conduit disposed on said shoulder hanger portion having a control valve disposed therein.

6. The combination of claim 5 wherein the outlet end portion of said conduit between said valve and said motor includes heat exchange means.

7. The combination of claim 6 wherein said conduit downstream of said heat exchange means includes pressure reduction and expansion means and said conduit downstream of said valve means is uncovered and constructed of a material having good heat transfer properties and thus adapted to be disposed in good heat trans fer relation with the water in which said propulsion assembly is immersed.

8. A back mounted underwater propulsion assembly for divers comprising a back mounting plate having upper and lower marginal edge portions and adapted to conform to and overlie the back of a diver, said upper marginal edge portion including a pair of laterally spaced inverted U-shaped forwardly projecting and downwardly opening shoulder hanger portions, means on said back mounting plate adapted to have at least one compressed fluid tank secured thereto, a generally J-shaped forwardly projecting and upwardly opening crotch engaging member carried by the lower edge portion of said back mounting plate, means mounting said crotch engaging member on said back mounting plate for adjustable positioning toward and away from said upper marginal edge portion, said adjustable positioning means including means releasably retaining said crotch engaging member in adjusted positions, said releasable retaining means including a remote control carried by one of said shoulder hanger portions.

9. A back mounted mounting plate adapted to conform to and overlie the back of a diver, said mounting plate including means for supporting tanks of compressed air therefrom and upper and lower marginal edge portions, shoulder engaging means carried by said upper marginal edge portion adapted to engage at least one of the shoulders of a diver, a generally J-shaped forwardly projecting, upwardly opening and at least semirigid crotch engaging member carried by the lower edge portion of said back mounting plate, means mounting said crotch engaging member on said back mounting plate for adjustable positioning toward and away from said upper marginal edge portion, said mounting means including means eccentrically mounting said crotch engaging member for adjustable positioning about an axis generally paralleling said mounting plate and extending from the upper marginal edge portion to the lower marginal edge portion of said mounting plate.

10. A back mounted mounting plate adapted to conform to and overlie the back of a diver, said mounting plate including means for supporting tanks of compressed air therefrom and upper and lower marginal edge portions, shoulder engaging means carried by said upper marginal edge portion adapted to engage at least one of the shoulders of a diver, a generally J-shaped forwardly projecting, upwardly opening and at least semi-rigid crotch engaging member carried by the lower edge portion of said back mounting plate, means mounting said crotch engaging member on said back mounting plate for adjustable positioning toward and away from said upper marginal edge portion, said mounting means including means resiliently mounting said crotch engaging memher on said mounting plate, said mounting means including means eccentrically mounting said crotch engaging member for adjustable positioning about an axis generally paralleling said mounting plate and extending from the upper marginal edge portion to the lower marginal edge portion of said mounting plate.

References Cited in the file of this patent UNITED STATES PATENTS 617,049 Rassinier Ian. 3, 1899 1,065,385 Bailey June 24, 1913 1,310,253 Shuman July 15, 1919 1,586,595 Barringer Tune 1, 1926 1,712,620 Johnson May 14, 1929 3,048,140 Davis Aug. 7, 1962 3,014,448 Fogarty et al Dec. 26, 1961 FOREIGN PATENTS 1,223,266 France Feb. 1, 1960 

8. A BACK MOUNTED UNDERWATER PROPULSION ASSEMBLY FOR DIVERS COMPRISING A BACK MOUNTING PLATE HAVING UPPER AND LOWER MARGINAL EDGE PORTIONS AND ADAPTED TO CONFORM TO AND OVERLIE THE BACK OF A DIVER, SAID UPPER MARGINAL EDGE PORTION INCLUDING A PAIR OF LATERALLY SPACED INVERTED U-SHAPED FORWARDLY PROJECTING AND DOWNWARDLY OPENING SHOULDER HANGER PORTIONS, MEANS ON SAID BACK MOUNTING PLATE ADAPTED TO HAVE AT LEAST ONE COMPRESSED FLUID TANK SECURED THERETO, A GENERALLY J-SHAPED FORWARDLY PROJECTING AND UPWARDLY OPENING CROTCH ENGAGING MEMBER CARRIED BY THE LOWER EDGE PORTION OF SAID 